1. Field of the Invention
One embodiment of the invention disclosed in this specification relates to a semiconductor device and a manufacturing method thereof.
2. Description of the Related Art
Transistors used for most flat panel displays typified by liquid crystal display devices and light-emitting display devices are formed using silicon semiconductors such as amorphous silicon, single crystal silicon, and polycrystalline silicon provided over glass substrates. Further, such a transistor employing such a silicon semiconductor is used in integrated circuits (ICs) and the like.
Further, the increase in size and definition of a flat panel display increases the driving frequency, the resistance, and the parasitic capacitance of a wiring, leading to wiring delay. In order to inhibit the wiring delay, a technique for forming a wiring using a low-resistance material such as copper, aluminum, gold, and silver has been studied (Patent Document 1).